Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Geophysical Research Letters
Groundwater is an important supply for drinking water and irrigation. Recharge from rainfall and snowmelt sets the upper limit for sustainable groundwater use and dictates the amount of discharge to streams as well as transpiration of deep-rooted plants. However, groundwater recharge rate at the regional to global scale is difficult to quantify due to its strong spatial heterogeneity and the sparse field measurements.
Berghuijs et al.  investigate the primary controls on global patterns of recharge based on a global synthesis of field measurements and derive a robust relationship linking recharge fraction to aridity (the ratio of potential evapotranspiration to precipitation). Then, they use the field-based relationship to estimate the groundwater recharge fraction based on aridity (excluding the permafrost and extremely humid regions).
Their estimate more accurately captures the observed global trend of recharge ratio than widely used global hydrological models. Moreover, their derived global recharge rate is twice of those from past estimates. These results suggest that existing global hydrological models must have also underestimated the role of groundwater in the global hydrological cycle.
Citation: Berghuijs, W. R., Luijendijk, E., Moeck, C., van der Velde, Y., & Allen, S. T. (2022). Global recharge data set indicates strengthened groundwater connection to surface fluxes. Geophysical Research Letters, 49, e2022GL099010. https://doi.org/10.1029/2022GL099010
—Guiling Wang, Associate Editor, Geophysical Research Letters